Make number of scrollback lines configurable

alacritty.yml

@@ -33,6 +33,9 @@ window:
   # Setting this to false will result in window without borders and title bar.
   decorations: true
 
+# How many lines of scrollback to keep
+scroll_history: 10000
+
 # Display tabs using this many cells (changes require restart)
 tabspaces: 8
 

alacritty_macos.yml

@@ -31,6 +31,9 @@ window:
   # Setting this to false will result in window without borders and title bar.
   decorations: true
 
+# How many lines of scrollback to keep
+scroll_history: 10000
+
 # Display tabs using this many cells (changes require restart)
 tabspaces: 8
 

src/config.rs

@@ -396,6 +396,14 @@ pub struct Config {
     /// Number of spaces in one tab
     #[serde(default="default_tabspaces", deserialize_with = "deserialize_tabspaces")]
     tabspaces: usize,
+
+    /// How much scrolling history to keep
+    #[serde(default="default_scroll_history")]
+    scroll_history: u32,
+}
+
+fn default_scroll_history() -> u32 {
+    10_000
 }
 
 fn failure_default_vec<'a, D, T>(deserializer: D) -> ::std::result::Result<Vec<T>, D::Error>
@@ -1244,6 +1252,10 @@ impl Config {
             .map(|path| path.into())
     }
 
+    pub fn scroll_history(&self) -> usize {
+        self.scroll_history as _
+    }
+
     pub fn write_defaults() -> io::Result<Cow<'static, Path>> {
         let path = ::xdg::BaseDirectories::with_prefix("alacritty")
             .map_err(|err| io::Error::new(io::ErrorKind::NotFound, ::std::error::Error::description(&err)))

src/grid/mod.rs

@@ -28,9 +28,6 @@ mod tests;
 mod storage;
 use self::storage::Storage;
 
-/// Lines to keep in scrollback buffer
-const SCROLLBACK_LINES: usize = 10_000;
-
 /// Convert a type to a linear index range.
 pub trait ToRange {
     fn to_range(&self) -> RangeInclusive<index::Linear>;
@@ -101,19 +98,8 @@ pub struct GridIterator<'a, T: 'a> {
 }
 
 impl<T: Copy + Clone> Grid<T> {
-    pub fn scroll_display(&mut self, count: isize) {
-        self.display_offset = min(
-                max((self.display_offset as isize) + count, 0isize) as usize,
-                self.scroll_limit
-            );
-    }
-
-    pub fn reset_scroll(&mut self) {
-        self.display_offset = 0;
-    }
-
-    pub fn new(lines: index::Line, cols: index::Column, template: T) -> Grid<T> {
-        let mut raw = Storage::with_capacity(*lines + SCROLLBACK_LINES, lines);
+    pub fn new(lines: index::Line, cols: index::Column, scrollback: usize, template: T) -> Grid<T> {
+        let mut raw = Storage::with_capacity(*lines + scrollback, lines);
         let template_row = Row::new(cols, &template);
 
         // Allocate all lines in the buffer, including scrollback history
@@ -137,6 +123,17 @@ impl<T: Copy + Clone> Grid<T> {
         }
     }
 
+    pub fn scroll_display(&mut self, count: isize) {
+        self.display_offset = min(
+                max((self.display_offset as isize) + count, 0isize) as usize,
+                self.scroll_limit
+            );
+    }
+
+    pub fn reset_scroll_display(&mut self) {
+        self.display_offset = 0;
+    }
+
     pub fn resize(&mut self, lines: index::Line, cols: index::Column) {
         // Check that there's actually work to do and return early if not
         if lines == self.lines && cols == self.cols {

src/term/mod.rs

@@ -808,7 +808,7 @@ impl Term {
     }
 
     pub fn reset_scroll(&mut self) {
-        self.grid.reset_scroll();
+        self.grid.reset_scroll_display();
     }
 
     #[inline]
@@ -822,7 +822,7 @@ impl Term {
         let num_cols = size.cols();
         let num_lines = size.lines();
 
-        let grid = Grid::new(num_lines, num_cols, template);
+        let grid = Grid::new(num_lines, num_cols, config.scroll_history(), template);
 
         let tabspaces = config.tabspaces();
         let tabs = IndexRange::from(Column(0)..grid.num_cols())